After Weather Scrub, Starlink Launch to Wait for Pair of National Security Missions

 In Space

A Falcon 9 rocket is seen just before bad weather forced SpaceX to scrub a launch attempt Monday with 60 more Starlink satellites. Credit: SpaceX

Continuing a dizzy­ing series of resched­uled launch­es from Florida’s Space Coast, poor weath­er at the Kennedy Space Center forced SpaceX to keep a Falcon 9 rocket and 60 Starlink broad­band satel­lites on the ground Monday. The Starlink launch is expect­ed to be delayed until Thursday, after a pair of nation­al secu­ri­ty mis­sions are set to blast off from Cape Canaveral Tuesday.

SpaceX halted the Falcon count­down Monday around 30 sec­onds before a liftoff from pad 39A that was sched­uled for an instan­ta­neous launch window at 10:22 a.m. EDT (1422 GMT). The company’s launch con­duc­tor said the count­down stopped due to weath­er vio­la­tions.

SpaceX did not imme­di­ate­ly set a new target launch date, but sources said the next oppor­tu­ni­ty to launch the mis­sion will be Thursday at around 9:17 a.m. EDT (1317 GMT).

Two rocket flights with U.S. nation­al secu­ri­ty pay­loads will take pri­or­i­ty on the Eastern Range’s launch sched­ule at Cape Canaveral.

A United Launch Alliance Delta 4‑Heavy rocket is set for liftoff at 12:02 a.m. EDT (0402 GMT) Tuesday from pad 37B at Cape Canaveral Air Force Station. Its mis­sion, code­named NROL-44, will deploy a clas­si­fied cargo for the National Reconnaissance Office, the agency which owns the U.S. government’s spy satel­lites.

Assuming the Delta 4‑Heavy gets off the ground early Tuesday, SpaceX will ready a sep­a­rate Falcon 9 rocket and a GPS nav­i­ga­tion satel­lite for liftoff from pad 40 at Cape Canaveral during a 15-minute window open­ing at 9:55 p.m. EDT Tuesday (0155 GMT Wednesday).

The three back-to-back launch­es — none direct­ly relat­ed to the other — are planned from sep­a­rate pads on the Space Coast.

The Delta 4‑Heavy rocket — the most pow­er­ful in ULA’s fleet — was orig­i­nal­ly sup­posed to launch in late August with the NROL-44 mis­sion. ULA scrubbed a launch attempt Aug. 27 to inves­ti­gate an issue with a launch pad pneu­mat­ics system, then a com­put­er sequencer com­mand­ed a hold just three sec­onds prior to liftoff Aug. 29 due to a fail­ure in a pres­sure reg­u­la­tor asso­ci­at­ed with one of the rocket’s three hydro­gen-fueled main engines.

The Aug. 29 count­down stopped after one of the rocket’s three RS-68A engines had ignit­ed. ULA’s launch team announced the abort­ed count­down as a fire­ball erupt­ed at the base of the rocket, a fiery fea­ture nor­mal­ly observed during the Delta 4‑Heavy’s engine start­up sequence.

The rocket was later drained of cryo­genic pro­pel­lants, and ULA engi­neers traced the prob­lem to a pres­sure reg­u­la­tor on the launch pad designed to flow helium gas to spin up rocket’s center engine for igni­tion. The reg­u­la­tor for the center did not open, prompt­ing the countdown’s auto­mat­ed sequencer to stop the count­down.

Tory Bruno, ULA’s pres­i­dent and CEO, tweet­ed that engi­neers refur­bished and tested all three pres­sure flow devices at pad 37B before pro­ceed­ing with anoth­er launch attempt.

ULA set Sept. 26 for the next launch attempt for the NROL-44 mis­sion, but offi­cials delayed the mis­sion again to inves­ti­gate a con­cern with the swing arm retrac­tion system at the Delta 4‑Heavy’s sea­side launch com­plex at Cape Canaveral. The swing arms, which feed liquid pro­pel­lants and con­di­tioned air to the vehi­cle, are designed to quick­ly retract away from the rocket at liftoff.

A Delta 4 rocket stands on pad 37B before a previous launch attempt on the NROL-44 mission. Credit: United Launch Alliance

ULA announced early Monday that the Delta 4‑Heavy rocket was on track for its launch oppor­tu­ni­ty just after mid­night Tuesday, Florida time.

The 235-foot-tall (71.6‑meter) Delta 4‑Heavy rocket will arc toward the east from Cape Canaveral over the Atlantic Ocean, tar­get­ing a near-cir­cu­lar geo­syn­chro­nous orbit more than 22,000 miles (nearly 36,000 kilo­me­ters) near the equa­tor.

While the NRO has not dis­closed any details about the Delta 4‑Heavy’s pay­load, ana­lysts believe it is likely a sig­nals intel­li­gence satel­lite with a giant anten­na that will be unfurled in space to stretch as big as a foot­ball field. If the ana­lysts are cor­rect, the space­craft will inter­cept tele­phone calls and data trans­mis­sions from U.S. adver­saries.

The Falcon 9 rocket sched­uled to blast off from pad 40 Tuesday night will loft the U.S. Space Force’s next Global Positioning System space­craft, the fourth in the latest gen­er­a­tion of GPS nav­i­ga­tion satel­lites made by Lockheed Martin.

The GPS 3 SV04 space­craft joins three pre­vi­ous Lockheed Martin-built GPS 3‑series satel­lites launched in December 2018, August 2019, and June 30 of this year.

But the offi­cial weath­er fore­cast at Cape Canaveral is iffy for the NROL-44 and GPS mis­sions Tuesday. There’s a 60 per­cent chance of good con­di­tions for launch of the Delta 4‑Heavy rocket early Tuesday, and just a 40 per­cent prob­a­bil­i­ty of accept­able weath­er for the Falcon 9 launch Tuesday night with the GPS satel­lite.

If the NROL-44 and GPS mis­sions take off as sched­uled, SpaceX could launch its Falcon 9 rocket from pad 39A Thursday with the next 60 Starlink satel­lites.

SpaceX has launched 715 Starlink satel­lites to date, and is near­ing the halfway point in a series of mis­sions since to place some 1,440 broad­band relay sta­tions into orbit to pro­vide high-speed Internet ser­vices over most of the world.

SpaceX has reg­u­la­to­ry approval from the Federal Communications Commission to launch up to 12,000 Starlink satel­lites for global broad­band ser­vice, and SpaceX has sig­naled its inten­tion to seek author­i­ty to put up anoth­er 30,000 Starlink plat­forms in the coming years.

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Follow Stephen Clark on Twitter: @StephenClark1.

Spaceflight Now source|articles

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